This invention relates to a flexible manufacturing system. More particularly, this invention relates to a flexible manufacturing system that allows for efficient product development and line changes to accommodate changes in product design.
Disposable, reusable and durable products such as diapers, adult incontinence articles, feminine hygiene tampons, sanitary napkins, underpants, shirts, shorts, swimsuits, gowns, pants, coats, gloves, scarves, surgical drapes, bibs, blankets, sheets, pillow cases, etc. may be manufactured on high speed converting lines. A converting line utilizes a web-based carrier to which many source materials, whether in a continuous web or discrete pieces, are processed and/or attached to the web to create a finished product.
Although a converting line may allow for high speed production, typical converting lines are inflexible in that line changes are time consuming and expensive. Product development and implementation of product upgrades usually require extensive testing and construction efforts. A product upgrade may, for example, require the following steps: constructing manual or handmade products incorporating the upgrade in order to test the concept and determine consumer acceptance of such an upgrade; constructing a machine production unit that may manufacture the product upgrade and/or the entire product incorporating the upgrade in order to determine product and process feasibility; constructing a high speed test stand that may manufacture the product upgrade in isolation at high speeds in order to test the feasibility of high speed manufacturing; constructing a prototype line that is able to make complete prototype products at high speeds; reconstructing a high speed production line to implement the process changes necessary for the product upgrade; and testing and debugging the production line. These efforts may be expensive and time consuming, especially when the reconstruction, testing and debugging steps lead to down time of a high speed production line. Then, when a product upgrade is rolled out on multiple production lines, the time and money required to implement even a small change in each individual line may increase dramatically. Often, the time and money required will be prohibitive, and highly desirable product upgrades may be delayed or even eliminated.
Attempts to increase the flexibility of a converting line have been made. U.S. Pat. No. 5,383,988 entitled xe2x80x9cModular Apparatus for Fabricating an Absorbent Article,xe2x80x9d issued to Thomas R. Herrmann et al. on Jan. 24, 1995 and U.S. Pat. No. 5,492,591 entitled xe2x80x9cModular Apparatus for Fabricating an Absorbent Article,xe2x80x9d issued to Thomas R. Herrmann et al. on Feb. 20, 1996, for example, describe a system for fabricating absorbent articles that includes a linear array of substantially identical frame modules joined together. A plurality of substantially identical, removable panels that support working devices are mounted to one face of the modules. The Herrmann references describe that mounting the working devices to the removable panels facilitates rapid installation, servicing, adjustment of the working devices and accommodates convenient observation of the operation of such devices.
Another attempt to increase the flexibility of a converting line is disclosed in U.S. Pat. No. 5,868,899 entitled xe2x80x9cProcess Line for the Production of Absorbent Disposable Products,xe2x80x9d issued to Dag H. Gundersen on Feb. 9, 1999, which describes a converting line for manufacturing disposable absorbent articles in which removable rectangular carrier plates that carry working devices are attached to vertical and horizontal posts. The posts are arranged sequentially in a framework on the same side of and parallel to a conveyor path movement. The Gundersen reference describes that the working devices in the converting line may be removed from, replaced or inserted into the converting line by removing, replacing or inserting the carrier plate to or from the framework of vertical and horizontal posts.
Although these efforts may allow for quicker physical construction or reconstruction of a converting line once the process for manufacturing a newly developed product has been developed off-line, the steps of constructing a machine production unit that may manufacture the product upgrade and/or the entire product incorporating the upgrade in order to determine product and process feasibility; constructing a high speed test stand that may manufacture the product upgrade in isolation at high speeds in order to test the feasibility of high speed manufacturing; and constructing a prototype line that is able to make complete prototype products at high speeds are still required. Also, the lines disclosed in the Herrmann and Gundersen references, once constructed, still require significant testing and debugging time before the line may be used for production of products. Thus, a method allowing for quicker product and process development is desired. Minimizing down time due to testing and debugging a production converting line after construction or reconstruction is also desirable.
The present invention comprises a flexible manufacturing system that allows for rapid product and process development and rapid construction or modification of a converting line that implements the new product and process development. The flexible manufacturing system of the present invention includes one or more modules and one or more local controllers. The one or more modules may be operated off-line in a standalone mode for product development and may also be inserted into a prototype line and/or an actual production line. The one or more modules may include one or more operational units. The one or more local controllers may be connected to the one or more modules in order to control the one or more operational units in a standalone mode. In the standalone mode, the one or more modules may be run as a test stand, and the one or more operational units and/or the one or more local controllers may be tested, adjusted or modified off-line of the flexible manufacturing system. Once a process for manufacturing a product upgrade including a portion of the new product has been developed and tested off-line, the one or more modules that include the operational units that will produce that portion of the new product may be inserted into the overall flexible manufacturing system, or one or more modules already in the converting line may be replaced with the module or modules that include the operational units that will produce that portion of the new product. The one or more local controllers may also utilize a reference signal to synchronize the operation of the one or more operational units of the one or more modules when the one or more modules are connected to the overall flexible manufacturing system.